Spring loaded heat saving device



F. R. VAUGHN Filed July 3, 1959 May 21, 1963 SPRING LOADED HEAT SAVING DEVICE WHHHHHIWIHIHH\ THERMOSTAT REVERSING CONTROL MOTO R BURNER 4 CONTROL MOTOR United States Patent 3 090 558 SPRING LOADED HEAT SAVING DEVICE Frank R. Vaughn, Madison, Wis., assignor to Albert H. lslarlgelllsi, Leo T. Schmit, and Pat Feeney, all of Pierre,

Filed July 3, 1959, Ser. No. 824,818 3 Claims. (Cl. 236-1) This invention relates to heat saving devices. More particularly, it relates to heat saving devices designed to be installed Within the stack of an electrically operated burner so as to cause the burner and heating system to function in a more efiicient and satisfactory manner.

It is a general object of my invention to provide a novel and improved heat saving device of simple and inexpen sive construction and operation.

A more specific object is to provide a novel and improved heat saving device which will effect a substantial saving in heat loss which normally accompanies the opening and closing of a damper in association with the activation and deactivation of a burner of a heat system.

Another object is to provide a novel and improved heat saving device for use in combination with an electrically actuated burner in which the burner is activated and deactivated in relation to the position of the damper in the stack of the burner.

Another object is to provide a novel and improved heat saving device for use in conjunction with an electrically actuated burner and the thermostat of a room, the device being so constructed and arranged as to be shifted between open and closed positions through an activating device which is controlled by the thermostat of a room and which is so constructed and arranged as to provide a substantial shorter opening period for the damper as compared to its closing period.

Another object is to provide a simple and inexpensive novel heat saving device which substantially reduces the heat loss during the opening period of the damper without reducing the length of the closing period thereof to a prohibitively short period such as to cause combustion gases to permeate throughout the home.

Another object is to provide a simple and inexpensive novel heat saving device constructed and arranged to shorten the normal opening period of the damper to substantially less than the normal closing period thereof whereby .a substantial loss in 'heat during the opening period is substantially eliminated and an adequate closing period is provided for the damper to permit the combustion gases to escape before the damper reaches fully closed position.

The optimum relationship between the damper and the firing of the oil burner furnace is that in which the damper will be opened or substantially open for a brief period immediately prior to the firing of the furnace in order to provide a proper draft therefor. In addition, the optimum relationship includes that in which the oil burner furnace would be deactivated a brief period immediately prior to the closing of the damper. This relationship is desirable because it is important that a good draft be created in the stack prior to the firing of the furnace so that complete oxidation of the fuels utilized by the furnace will result at once upon the initial firing of the furnace and thereby prevent smoking which, of course, is caused by incomplete oxidation of the fuel. The deactivation of the oil burner furance prior to or upon the closing of the damper is highly desirable to insure that all of the combustion gases escape through the stack before the damper is closed. If such gases are locked in by early closing of the damper, seepage of the fumes will make the interior of the house being heated by the furnace disagreeable or unpleasant. I have found however, that the opening period and the closing period are not necessanly of equal length and, in fact, can preferably be made of different lengths. For example, I have discovered that a certain minimum period is required after the burner is deactivated to permit the combustion gases to escape through the stack. If the damper is closed prematurely, these gases will escape into the interior of the home which of course, is objectionable. I have found that if an ample closing period is provided to permit these gases to escape before the damper is closed subsequent to the deactivation of the burner, the opening period, if it is made of equal length, will be unnecessarily long. In other words, I have found that the period during which the stack must be open prior to activation of the burner can be substantially less than the period during which the damper is permitted to remain open subsequent to the deactivation of the burner. I have found that a very substantial loss of heat results from this unnecessarily prolonged period during which the damper is opened prior to the activation of the burner, if the period prior to deactivation of the burner is equal to the period during which the damper closes subsequent to the deactivation of the burner as has heretofore been the practice. My heat saving device is designed to eliminate this substantial heat loss in a simple and efficient manner without impairing the practical and desirable results obtained by opening the damper prior to activation of the burner and closing it subsequent to its deactivation.

These and other objects and advantages of my invention will more fully appear from the following description made in connection with the accompanying drawings wherein like reference characters refer to the samev or similar parts throughout the several views, and in which:

FIG. 1 is a plan view of my heat saving device;

FIG. 2 is a side elevational view of the same with portions of the housing surrounding the motor broken away to show the interior thereof; and

FIG. 3 is a diagrammatic view illustrating the relationships which exist between the thermos-tat, motor, burner, burner control, and switch leading to :the burner control.

One embodiment of my invention as shown in FIGS. 1-3, includes the damper 5 pivotally mounted in a section of conduit 6 which is adapted to 'be inserted in the stack of a burner identified by the numeral 7 in FIG. 3. The burner 7 is provided with a burner control 8 which is connected to a source of power 9. A switch 10 is interposed within the circuit to the burner control so that when the switch is closed the burner will be activated and when it is opened, it will be deactivated. The switch 10- is opened and closed by a switch arm '11 which is fixedly mounted upon and rotates with the pivot rod 12 which carries the damper 5 and extends through the conduit section 6 as best shown in FIG. 1. This pivot rod 12 is directly connected to the motor 13 as best shown in FIGS. 1 and 2.

7 The motor 13 has a motor reversing control 14 which is activated by the thermostat 15 normally found in the room of the home. The motor of course, is connected to a source of power 16 so that each time the thermostat actuates the motor reversing control 14, the motor will al ternately rotate in opposite directions. The mechanical connection between the motor 13 and the switch 10 (which is comprised of the switch arm 11) is indicated in FIG. 3 by broken lines.

The damper 5 when in closed position is in generally horizontal position so as to extend transversely across the entire internal area of the conduit section 6 and for all essential purposes, closes off the interior thereof to prevent the escape of hot air upwardly therethrough. When the pivot arm 12 pivots through a are from vertical to horizontal, the damper 5 will extend vertically in open position as shown in FIG. 1. The device as shown is provided with a type of motor 13 which W111 cause the damper'S to swing within this 90 are between open and closed positions.

The motor 13 is mounted on a mounting bracket 17 which as shown is attached to the conduit section 6 so that the entire unit may be interposed within the stack of an electrically actuated burner to provide the desired functions. When so inserted, the lead lines 18 and 19' from the thermostat 15 are connected to the motor reversing control 14 (not shown in FIGS. 1 and 2) so that the thermostat directly controls the energization and de-energization of the motor 13. The thermostat 15 is of the conventional type having temperature range limits which may be varied as desired, the circuit through the thermostat being closed by the thermostat contact when the temperature reaches the lower temperature range limit and being opened when the temperature of the room reaches the upper temperature limit. This is conventional in thermostats and is well known in the art and it is therefore deemed unnecessary to describe the construction thereof in greater detail.

The motor 13 is a shaded pole two wire reversible type motor in which the reversing is done by shading in the motor. It has an isolated lower-energy secondary winding which, if shorted by a room thermostat or the equivalent, affects the motor field to cause reverse motor rotation. The control of the direction of the motor is accomplished through the control circuit which includes the leads 18 and 19 and the thermostat 15. The coils of this motor have induced low voltage generally varying from 7 to 15 volts according to the motor type but are not connected directly to the power line. When the leads are shorted externally the circuit varies from 0.4 amperes to 0.7 amperes according to the motor type. The type motor which I have found most preferable is a 115 volt AC. 60 cycle motor, -10 watts, which is known as a Model Acro T4178A 90 and is obtainable on the market from the Acro Division of the Robertshaw-Fulton Control Company, Columbus, Ohio. This type of motor is of a special type that rotates in one direction when the control circuit is opened and in the opposite direction when the control circuit is closed or shorted. These motors can be stopped only by stalling them mechanically or by opening the A.C. power line. These motors may be stalled continuously without danger of burning out.

The motor 13 is provided with a stopping pin in the gear train to mechanically stall the motor after it has run through a 90 are or phase. The speed of the motor is such that it would normally run through this 90 phase in approximately 25 seconds, if unaffected by any outside urging. In other words, the motor as constructed can run through a 90 phase and at the close of that phase it will be mechanically stalled so that it will cease to run even though it remains continuously energized. This motor is of a type which can be so continuously stalled without damage to the motor. FIGS. 1-2 show a stopping pin 20 in the gear train which engages an abutment 21 secured to the mounting plate of the motor when the switch arm swings from horizontal switch engaging position to vertically extending position as the damper 5 closes. The motor 13 is mechanically stalled at the other end of its 90 phase by a second pin 22 engaging the abutment 21 and arresting its further rotation. The motor 13 may be mechanically stalled through the use of internal stops as shown or of course, it could be mechanically stalled by other means, any one of which would function to mechanically stop the motor from running at the ends of a 90 phase even though it remains energized.

As pointed out above, the motor 13 is constantly energized and will run whenever the control circuit is such as to permit its running, which means Whenever the control circuit will permit it to run away from the particular stopping'pin which may have arrested its last motion or rotation. When the temperature of the room in which the thermostat 15 is placed is as warm as the upper range limits of the thermostat, the thermostat will be opened this condition, the damper 5 will be in substantially horizontal or closed position and the motor will be prevented from running by the abutment 21 and the stopping pin 20. When the temperature of the room has reduced sufliciently to reach the lower range. limits of the thermostat 15, the contacts in the thermostat 15 will close and the control circuit for the motor M will be closed. This will cause the direction of rotation of the motor to be reversed and the damper 5 will be gradually moved to open position until the pin 22 engages the abutment 21.

As pointed out previously, however, I have discovered that a substantial reduction in heat loss can be allected by shortening the opening period of the damper 5 and thereby preventing a substantial loss of heat from the home. To accomplish this, I have provided spring loading for the damper 5 by means of a spring 23 which is secured at one end to the housing 24 of the motor and at its other end to the outer end of the switch arm 11 as best shown in FIGS. 1 and 2. From this it can be seen that the damper 5 is constantly urged toward open position and is constantly urged against being moved toward closed position. The net result of this spring loading is to substantially shorten the opening period and to extend the closing period of the damper 5. As a result, this device has an opening period of approximately 20 to 22 seconds and closes in approximately 35 to 36 seconds. Thus, it can be readily seen that the opening period is substantially less in length than the closing period and the opening period has been substantially reduced from that as heretofore required with previous heat saving devices of this type.

The damper 5 will be in closed position so long as the room in which the thermostat 15 is disposed will be at the desired temperature. When the temperature of the room drops however, the contacts of the thermostat 15 will close and this will cause the motor 13 by means of the motor reversing control 14 to be actuated in a direction such as to turn the damper 5 toward open position. The normal speed of the motor 13 will be accentuated by the action of the spring 23 so that the damper 5 will open quickly. As soon as the damper 5 reaches open position, the switch arm 11 engages the switch 10 which closes the circuit to the burner control and actuates the burner 7. The burner will then operate until the room reaches the desired level and the contacts of the thermostat open. The opening of the thermostat contacts will again actuate the motor reversing control 14 and cause the motor 13 to operate in the opposite direction. In doing so however, the motor 13 will have to overcome the resilient urging of the spring 23 which retards the opening operation and slows down the motor so that the opening period will be substantially longer than the closing period for the damper 5. As soon as the damper 5 leaves open position, the

F arm 11 will disengage the switch 10 so that the switch 10 ening the opening period and yet maintaining the closing period for the damper sufficiently long to maintain the necessary draft within the stack to cause the combustion gases to be carried out the stack before the damper 5 reaches fully closed position.

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportion of the various parts without departing from the scope of our invention.

What is claimed is:

1. In a heat saving unit for use in conjunction with an electrically actuated burner having an electrical control circuit, a burner stack, a damper pivotally mounted within said stack for movement between open and closed posi tions, a reversible motor having excitation and control windings connected to said damper in rotational driving relation and having said excitation winding continuously energized when connected to a source of power, said motor being constructed and arranged to reverse itself when its control circuit is closed, a room thermostat connected to said motor control winding to utilize the same as a control circuit to be opened and closed at different room temperatures, a switch mechanism connected with said damper and moving between open and closed positions with the movement of said damper, said switch mechanism adapted to be connected in the electrical control circuit of such a burner in circuit closing and opening relation and being constructed and arranged to close the circuit to the burner when said damper is opened and to open the circuit to the burner when said damper moves away from open position, and resilient mechanism connected with said damper and urging the same toward open position whereby said damper will open in appreciably less time than it will close to thereby effect a heat References Cited in the file of this patent UNITED STATES PATENTS 2,037,363 Branche Apr. 14, 1936 2,039,300 Drake May 5, 1936 2,155,642 Dewey Apr. 25, 1939 2,241,590 Field May 13, 1941 2,246,566 Ames et a1. June 24, 1941 2,280,062 Craig Apr. 21, 1942 2,285,749 Stuart June 9, 1942 2,465,325 Kronmiller Mar. 22, 1949 

1. IN A HEAT SAVING UNIT FOR USE IN CONJUNCTION WITH AN ELECTRICALLY ACTUATED BURNER HAVING AN ELECTRICAL CONTROL CIRCUIT, A BURNER STACK, A DAMPER PIVOTALLY MOUNTED WITHIN SAID STACK FOR MOVEMENT BETWEEN OPEN AND CLOSE POSITIONS, A REVERSIBLE MOTOR HAVING EXCITATION AND CONTROL WINDINGS CONNECTED TO SAID DAMPER IN ROTATIONAL AND CONTROL RELATION AND HAVING SAID EXCITATION WINDING CONTINOUSLY ENERGIZED WHEN CONNECTED TO A SOURCE OF POWER, SAID MOTOR BEING CONSTRUCTED AND ARRANGED TO REVERSE ITSELF WHEN ITS CONTROL CIRCUIT IS CLOSED, A ROOM THERMOSTAT CONNECTED TO SAID MOTOR CONTROL WINDING TO UTILIZE THE SAME AS A CONTROL CIRCUIT TO BE OPENED AND CLOSED AT DIFFERENT ROOM TEMPERATURES, A SWITCH MECHANISM CONNECTED WITH SAID DAMPER AND MOVING BETWEEN OPEN AND CLOSE POSITIONS WITH THE MOVEMENT OF SAID DAMPER, SAID SWITCH MECHANISM ADAPTED TO BE CONNECTED IN THE ELECTRICAL CONTROL CIRCUIT OF SUCH A BURNER IN CIRCUIT CLOSING AND OPENING RELATION AND BEING CONSTRUCTED AND ARRANGED TO CLOSE THE CIRCUIT TO THE BURNER WHEN SAID DAMPER IS OPENED AND TO OPEN THE CIRCUIT TO THE BURNER WHEN SAID DAMPER MOVES AWAY FROM OPEN POSITION, AND RESILIENT MECHANISM CONNECTED WITH SAID DAMPER AND URGING THE SAME TOWARD OPEN POSITION WHEREBY SAID DAMPER WILL OPEN IN APPRECIABLY LESS TIME THAN IT WILL CLOSE TO THEREBY EFFECT A HEAT SAVING. 